I've got to get around to adding North by Northwest to my favorites list.
I'm mentioning the DVD now because it's been marked down to $15 at online retailers and at many stores. I paid $20 or $30 for it when it first came out and it was worth every penny. One of my favorite films, the DVD is gorgeous, the film looks better than ever before letterboxed and all cleaned up. It's now $15 and if you've got a DVD player, there's no reason not to own it.
The documentary that comes with it is pretty good and the commentary track by Ernie Lehman is pretty darn cool, too.